My thoughts and reminders as GIS Librarian at the University of Texas at Arlington. This blog is primarily a way for me to jot down my ideas and also to record notes from other blogs and feeds out there. Everyone is welcome to follow along if you like.

Thursday, June 29, 2006

This is an intriguing position. As gleaned from the job posting, the Lehman Social Sciences Library has two professional GIS positions: the GIS/Map Librarian and the currently available position, GIS/Metadata Librarian.

This position will focus on the cataloging/metadata maintenance and distribution of geospatial data. That is a wonderful setup that I am envious of as I think of the fantastic spatial catalog we can build if we had someone devoted entirely to it's development and maintenance. It is possible... This prompts me to draft a request for a new professional position or perhaps a professional.

Here are some snippets:

"Work with colleagues from a variety of Library, IT, academic departments and University institutes in the design and creation of a searchable and easily accessible spatial data catalog that allows for remote access to spatial data collection."

"Work with the GIS/Map Librarian and the Head of EDS to provide reference services, outreach and instruction in EDS. This includes: providing one-on-one consultations, assisting in instruction sessions, and training student assistants working in the unit."

There is no mention of salary, but these perks are extremely enticing:

We offer excellent benefits including 100% Columbia tuition exemption for self and family and assistance with University housing. Columbia will also pay 50% tuition for your dependent child who is a candidate for an undergraduate degree at another accredited college or university.

Wednesday, June 28, 2006

Just came across geoLibro, a new blog to enter the geospatial-library blogosphere. From the blog description, "let this blog document the installation of library-centric GIS services at Purdue University."

The initial post, dated June 1, states that Purdue Libraries is looking to create these library-centric GIS services pretty much from the ground up. Their new GIS Librarian, who authors this blog, starts at Purdue in August. I am sure going to keep up with this blog to see how Purdue Library goes about setting up their "pimped-out desktop machines...[and] also a server to run ArcSDE and ArcIMS..."

Do GIS Librarians have the best jobs out there, or what? ... What? Eh? ... Salary not so good, you say? Well sure, but the job is so much fun and rewarding that it is all worth it.

Here are the GIS library and other academic lab blogs that I monitor (copy/pasted from my blogroll listed on the right):

As is to be expected, one of the most popular GIS requests that I have received lately (especially last Spring semester) are data resources concerning the H5N1 Wild Bird flu virus. There are some great resources out there, the best that I am aware of I will list below.

Earlier this summer, a student researching the epidemiology of the virus needed a shapefile of the common worldwide migratory bird flyways. I was unable to locate such a shapefile. If someone knows of such an available file (free or not) out there, please leave a comment here to let me know about it. However, we were able to locate several static maps (images) of migratory bird flyways. I advised the student on how to georeference and digitize such a static map to create a feature class. Unfortunately I have not heard back from the student since then so I do not know if they were successful.

Declan Butler, reporter for Nature, has created a super-fantastic Google Earth resource. These freely available KML files contain both human and poultry cases of avian flu. More information can be found on Declan's blog.

Great resource for worldwide, country-level, disease data. Provides data tables and even an interactive mapping interface. The data tables are the most useful to me as there is even a download to Excel option.

I know there must be all sorts of other great resources out there, but the sources I listed above has suited all of my needs thus far.

Sunday, June 25, 2006

A growing request by students on campus lately is the accurate geocoding of addresses. My opinion is that with the high accessibility of aerial imagery these days, students want geocoded addresses to be placed exactly on the house or business. I have been recommending these students to geocode their addresses based on parcel boundaries as opposed to using a street file. I want to take this opportunity to organize my thoughts about the steps needed to geocode directly to the parcel boundaries, specifically using ArcGIS desktop software.

Of course, you will get much better precision geocoding an address to the parcel boundary. For example, if I look at the Google Map image of that old rundown house I lived in while a student in Buffalo, you will see the marker get close but not quite exactly right on. The house is actually the next to last house near the dead-end. StreetMap USA will not geocode the address with high enough precision, nor will Yahoo! Maps, and of course TIGER/Line geocoding (poor-man's geocoding) will be way off.

The only solution for a high level of accuracy is to geocode addresses based on the parcel boundaries, provided the parcel boundary feature class is accurate as well.

So, here's the steps.

Of course first you must obtain the parcel polygon containing the address information for each parcel.

This is the important step. Now we're ready to create our geocoding service. In ArcToolbox, launch Geocoding Tools/Create Address Locator. The style that we want is 'US One Address'. You can see in the Field Map that the street number and the street name must be separated. Fill out the form and let 'r rip.

Now that we've got the geocoding service set up properly, we can geocode as we normally would, but using the service we just created. All matched addresses will be placed exactly in the parcel centroid.

Now, be warned that the unmatched percentage might be higher than you anticipated. This is because the 'US One Address' geocoding style will either find a polygon containing that address or it will not. There is no estimating or approximating. Conversely, standard street geocoding finds approximate address information between nodes. For example, 450 Happy Gilmore Street will be placed exactly inbetween the 400 node and the 500 node of Happy Gilmore Street. What if there is no physical address at 450 HG Street? The point will still match there. What if 450 HG Street is the first house on the 400 block of HG Street? The point will still be placed exactly in the center between the nodes.

Saturday, June 24, 2006

These are the freely available applications and services that make up my own personal free GIS.Individually, many freely available applications do not of themselves constitute a full geographic information system, but when these are all pulled together within one suite of tools...Well, it is remarkable what someone can do without spending a cent.(And without needing to spend an enormous amount of time developing your own applications out of open source components or needing to learn, or install, complex applications, such as GRASS GIS.)

To all of you wonderful and generous developers out there who have spent your own resources to create these applications/services, I give you a sincere and heart-felt thank you for making it so easy and wonderful for the rest of us.Thank you.

As reported here, fGIS is no longer freely available as of November 7, 2005.Big time bummer.However, this page states: “You can continue to use and freely share versions of fGIS released before November 7, 2005.” Older versiona of fGIS can be downloaded from ForestPal.com.

More user-friendly interface than SAGA.

There are some great utilities available in fGIS that are hard to find elsewhere.

Powerful shapefile editing capabilities.

Shapefile utilities: clip, merge, table join, select, intersectct

3D view

Nice map layout features

Georeferencing tools

Create a point shapefile from geocoded addresses (table containing XY)

I am fond of this little freeware application because of its small size (0.97 MB), very user-friendly interface (similar in ways to ArcView 3), and its simplicity.Many users of GIS simply want to be able to download some TIGER/Line files and join them to some Census data to create static maps.This is the software I always recommend for such purposes.

One of the powerful features of GeoDa is the linking and brushing between all tables, maps, and graphs.For example, select the outliers on a box-plot graph and these features are also highlighted on all other charts, tables, and maps.

In the bulleted list, I pointed out mainly the spatial analysis tools in which GeoDa specializes.However, I do want to point out that this application does indeed have numerous standard GIS functionality, such as table joins, attribute calculations, table to points, etc.If GeoDa were to add just a few small standard GIS functions to its repertoire, it could very well serve as an independent GIS application.

One other thing that must be pointed out is the most excellent documentation.In particular, the 244 page Exploring Spatial Datwith GeoDaDa: A Workbook (PDF) serves as an entire course on spatial analysis.

Functionality similar to GeoDa, but much more flexible and dynamic as it is completely open source (written in Python).

Python developed, open source, cross-platform.The sample application distributed with the code is simply an example of the applications that can be developed using STARS.

Anyone interested in open source Python GIS should take a look at PySAL.

LINUX GIS TOOLS FOR THE LINUX-INTIMIDATED

There are some fantastic open source resources out there that people swear work so wonderful on the Linux platform.However, if you are entirely dependent on Windows or merely dabble in Linux (like me), compiling and installing the applications can be more difficult than actually using them.Even if you can get your hands on a good binary file, it is likely that you will not have all of the required dependencies.OK, you can see my Linux frustration here.Anyway, here are a couple of tools that make it easy for absolutely anyone to install the applications and so the only remaining obstacle is using them…

This is the best all-in-one free remote sensing application that I have used.

ScanEx offers two different freeware applications, ScanMagic Lite and ScanMagic LL.These two offer similar features, but not exactly the same.Download both to get the full potential from their offerings.

Do I even need to write something here?GE is a wonderful and exciting application that is impacting the geospatial community in profound ways.

There are some fantastic free tools out there for converting shapefiles into GE’s KML format. A good one is Shape2Earth. Of course, MapInfo supports exporting to KML and there are numerous 3rd party ArcGIS extensions as well.

Wednesday, June 21, 2006

TableTools is a new (to me) Firefox browser extension that is really, really cool.

Tables on the web become interactive with this extension. Right-click menu includes sorting (yes, actually sort previously static tables), filtering (yes, just like Excel's auto-filter), and copying as tab-delimited or HTML.

A great use of this extension is to use it with BatchGeocode.com. As many folks are aware, BatchGeocode.com is a free batch address geocoder that uses the public Yahoo! Maps Geocoding API to take a pasted tab-delimited table and spit out an identical table with lat/long coords (as well as a Yahoo! Maps mashup and Google Earth KML file of the first 100 points). Using the TableTools extension, a table of addresses on the web can be copied directly to tab-delimited format, and then pasted directly into BatchGeocode.com without ever opening Excel. Now THAT is a beautiful thing, eh?

All of the tables in the 125th edition (2006) of the Statistical Abstract of the United States are available in Excel format. This is a huge leap forward from PDF, which is how StatAb has traditionally been published online.

I really appreciate that all tables have static URLs. This means that I can save and share these resources using the Zoho Sheet Online Excel Viewer. I have previously blogged about Zoho Sheet, a powerful (& free) Web 2.0 spreadsheet application. The Online Excel Viewer allows users to view and interact with existing Microsoft Excel spreadsheets entirely over the web.

Here are a few examples of using Zoho Sheet to view these static StatAb Excel files:

About Me

Father of two boys, married to an engineering student, work as a GIS librarian & adjunct professor, love sci-fi/fantasy (especially Gene Wolfe, Rudy Rucker, Jeff Noon, Frank Herbert), table tennis, and a follower of the specific carbohydrate diet since 11/2005; vegan since 07/2006; faltered in the first half of 2008 but am working hard to get back on track.